about my Boyfriends birthday & his mum

[crazyhamsterdisguisedasahippo]

First AIBU but I really need to know if I am .

Its my Bfs birthday on Tuesday , he has just told me he is going for a meal with his mum & family Tuesday evening so will be busy from 4 - 8 .
I have not been invited despite us been together for 3 years (we don't live together) .
He is working Tuesday morning until 1pm & i have appointments Tuesday from 1-4 (several appointments) .
He says it is not fair that i can't see him on his birthday & expects me to palm my Ds off on my Dm on a school night so i can take him out I have told him i won't do this as Ds comes first & i told him to ask his mum to make it later or for the day after & he can't as she will be upset (huge case of pfb) .
I thought i was his family but apparently not as he does everything his mum says even if it means cancelling our plans

Am I been unreasonable to think that after 3 years he would see me as his family as well as his mum & sometimes put our relationship first or should I just suck it up

[Numberlock]

So... not Do

[crazyhamsterdisguisedasapanda]

what do you mean by post-mortem